Low-profile, high-strength latch



Nov. 22, 1966 w. c. BoYcE ETAL 3,286,317

LOW-PROFILE; HIGH-STRENGTH LATCH Filed Feb. 27, 1964 1NVENTORS. o cfUnited States Patent O 3,286,317 Low-enorme, HIGH-STRENGTH LATCH WilliamC. Boyce, Dallas, and Howard E. Freeman,

This invention relates to devices for use in securing two rigid, orsemirigid parts, for example, such as the protective suits used inrestraint systems by astnonauts or occupants of high performanceaircraft. More particularly, it comprises a high strength, low pnofile,latch which can be quickly and easily closed or opened and which iscapable Iof securely fastening a breastplate to a back plate of arestraint system such as that described in application Serial No.347,980, filed on even date herewith.

There are many conventional buckle, strap or cable fasteners which lareelrnployedI for securing purposes; however, they are sometimes clumsy,insecure, hard to adjust or `difficult .to fasten or unfasten.

Briefly, this invention comprises three elements, the first of which ismovably attached to a second element. In use, a third element isinserted into an opening in the second element and the first element isciosed over it to form a lock.

It is an object of this invention rto overcome the above deficiencies inconventional latches by providing a strong, secure device with a tlowproiile which will be easy to fasten and unfasten.

It is further object to provide such a device which can be economicallyproduced from easily obtainable, conventional materials that lendthemselves to mass pro-duction manufacturing techniques.

These and other advantages will be apparent upon consideration of theiollowing detailed description, especially when taken in conjunctionwith the accompanying drawings, in which:

FIGURE 1 is a plan view of the latch of Ithis invention with t-heelements locked position;

FIGURE 2 is a view in section taken along lines II-II of FIGURE 1 andincludes portions of the elements to be secured together;

FIGURE 3 is a plan view of the back plate fitting of .the latch of thisinvention;

FIGURE 4 is a sectional view of FIGURE 3 taken along lines IV-IV; and

FIGURE 5 is a detail of t-he cam of the lock Iplate.

The device of this invention is capable of maintaining two portions thatare required to be secured together in a fixed relationship. As can beseen in FIGURE 2, a back plate is to be attached to a breastplate 12 ofa protective suit of the type described inthe aforementioned applicationrelating to a hard shell restraint system. The breastplate 12 hasriveted thereto by means of rivets 15 a ygenerally U-shaped .orbifurcated member 14 which serves as a breastplate fitting. Theextremity of the legs formed by Ithe bifurcated member 14 has hingedthereto a lock plate 16. The securing of the two elements is achieved bymeans of a pin 18 which is peened over or swaged at its ends to preventaccidental removal.

The lock plate 16 has formed as a pant thereof a cam 20, the cam surface24 of Wthich is eccentric with respect to its pivot axis or the holelaccommodating the pin 18. In practice, the lock plate 16 might be madeby welding it, for example, at 22 to the eccentric cam 20 (FIGURE 5).The eccentric surface of the cam is designated with the numeral 24 andbears against la back plate fitting 26 which ICC is secured to the backplate 10 Iby means of rivets 28. The back plete fitting 26 has concave,generally cylindrical grooves 30 which form segments of a cylinder ateaclh end thereof. One segment mates with the cam surface 24 while theother mates with a convex surface indicated at 32 on the breastplatefitting.

To operate the latch the bneastplate 12 and the back plate are drawntogether with the breastplate fitting 14 having its lock plate 16rotated out of its locking, camming position. Tihe bifurcatedbreastplate fitting 14 and the cam 20 of the lock plate 16 surround theback plate fitting 26. Rotation of the lock plate 16 rotates the cam 20so that the cam surface 24 causes the cylindrical contours to engage oneanother, thereby firmly fastening the breastplate 12 to tlhe back plateor back torso shell 10. The locking plate 16 has provided at one end apair of tabs 34 which are bent upwardly to facilitate lifting of thelock plate to engage the latch.

In fuse with the aforementioned hard shell restraint system a harnesscable which passes over the lock plate for the shoulder harness protectsthe latch against inertial loads. A groove is provided at 36 toaccommodate the shoulder hanness cable. Where a cable is not to beutilized the lock plate could be secured by a conventional spring |orsnap type retainer.

Thus, there has been described a low profile, high strength latch which,because of the cylindrical contour engagement, is capable `of carryingshear loads in all directions as Well as torsional and bending moments.

Although the invention has been described With reference to a particularembodiment, it will be understood to those skilled i-n the art that theinvention is capable of a variety of alternative embodiments Within thespirit and scope of the appended claims.

We claim:

1. A low profile high strength latch for joining two objects comprisinga bifurcated member secured to one of said objects, said member having aconvex surface within the biflrcated portion of said member, oppositeits open en a cam member rotatably mounted proximate the ends of andbetween the legs of said bifurcated member, and

a fitting on the other of said objects, said fitting comprising a fiatplate of a size to fit Withi-n the bifurcated portion of said bifurcatedmember, with opposite edges of said fitting having concave groovestherein for engagement with said convex surface of said bifurcatedmember and said cam.

2. A latch as defined in claim 1 wherein said concave and convexsurfaces are segments of a cylinder.

3. A latch as defined in claim 1 including a lock plate secured to saidcam member for operation thereof.

References Cited by the Examiner UNITED STATES PATENTS 649,831 5/ 1900Fuller 287-103 1,091,344 3/1914 Jenks 24-68 1,220,777 3/1917 Neider24-211 1,233,215 7/1917 Gates 24-223 FOREIGN PATENTS `663,925 4/ 1929France.

789,992 1/ 1958 Great Britain.

WILLIAM FELDMAN, Primary Examiner.

E. SIMONSEN, Assistant Examiner.

1. A LOW PROFILE HIGH STRENGTH LATCH FOR JOINING TWO OBJECTS COMPRISINGA BIFURCATED MEMBER SECURED TO ONE OF SAID OBJECTS, SAID MEMBER HAVING ACONVEX SURFACE WITHIN THE BIFURCATED PORTION OF SAID MEMBER, OPPOSITEITS OPEN END, A CAM MEMBER ROTATABLY MOUNTED PROXIMATE THE ENDS OF ANDBETWEEN THE LEGS OF SAID BIFURCATEDMEMBER, AND A FITTING ON THE OTHER OFSAID OBJECTS, SAID FITTING COMPRISING A FLAT PLATE OF A SIZE TO FITWITHIN THE BIFURCATED PORTION OF SAID BIFURCATED MEMBER, WITH OPPOSITEEDGES OF SAID FITTING HAVING CONCAVE GROOVES THEREIN FOR ENGAGEMENT WITHSAID CONVEX SURFACE OF SAID BIFURCATED MEMBER AND SAID CAM.